1. Field of the Invention
This invention relates to materials which may be utilized to form elastomers at room temperature and to the elastomers thus formed.
2. Description of the Prior Art
It is well known to use elastomers as binders for explosives, propellants and the like. Literally thousands of elastomers have been disclosed as being useful for such purposes. Despite the wide variety of elastomeric binders available, those wich have found wide spread use in propellants and the like have had one problem in common. That problem is the fact that they have only been curable at elevated temperatures. As a result of the need for elevated temperature cures, several sub-problems have developed.
One sub-problem or, in actuality, series of sub-problems stems from the fact that an oven is required if cure is to be carried out at an elevated temperature. Ovens are expensive. They require space. Elevated temperature cures require time. A propellant or the like must be handled in order to get in it and out of the oven. Finally, if an oven malfunctions, cure is not carried out properly and a batch of prepolymer is wasted.
More important than the sub-problems related to oven, are a series of sub-problems related to the fact that stresses are induced into an elastomer when it is cooled to ambient temperature after having been cured at an elevated temperature. These stresses often lead to cracking. Cracking is especially likely to occur if the elastomer is subjected to temperature cycling and such cycling is the rule rather than the exception.
Current theory in stress analysis is that once it is induced, stress is never entirely removed. Thus, if an elastomer is cooled below room temperature and subsequently raised back to room temperature those stresses that are induced by the cooling never completely disappear.
Since stress is induced when an elastomer is cooled from cure temperature to ambient, it would be advantageous if cure could take place at ambient. This would eliminate a portion of the life history of a propellant or the like during which stress is induced.